Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
  • B60C11/03—Tread patterns
  • B60C11/13—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping
  • B60C11/1376—Three dimensional block surfaces departing from the enveloping tread contour
  • B60C11/1392—Three dimensional block surfaces departing from the enveloping tread contour with chamfered block edges
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
  • B60C11/03—Tread patterns
  • B60C11/0306—Patterns comprising block rows or discontinuous ribs
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
  • B60C11/03—Tread patterns
  • B60C2011/0337—Tread patterns characterised by particular design features of the pattern
  • B60C2011/0339—Grooves
  • B60C2011/0358—Lateral grooves, i.e. having an angle of 45 to 90 degees to the equatorial plane
  • B60C2011/0365—Lateral grooves, i.e. having an angle of 45 to 90 degees to the equatorial plane characterised by width
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
  • B60C11/03—Tread patterns
  • B60C11/12—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes
  • B60C2011/129—Sipe density, i.e. the distance between the sipes within the pattern

Definitions

• This invention relates generally to tires that are configured for improved snow performance, and, more specifically, to a tire having one or more lateral grooves with a predetermined width, each of which having one or more chamfers for improved snow performance.
• Particular embodiments of the present invention include a tire with improved snow traction that has lateral and circumferential directions and includes a tread with a circumference and at least one lateral groove located thereon.
• the groove has at least one chamfer found where the groove intersects the circumference of the tire, said groove having a predetermined depth and width and sidewalls having predetermined draft angles.
• the width of the groove ranges from approximately 2 to 4 mm and preferably from approximately 2.6 to 3.6 mm. In some cases, the width of the groove is approximately 3 mm.
• the chamfer forms approximately a 45 degree angle with the tangent of the circumference of the tire.
• the depth and width of the chamfer could be 1.5 mm.
• the depth of the groove could be approximately 7 mm.
• the groove comprises a second chamfer that is opposite of the first chamfer.
• the circumference of the tire may have a plurality of lateral grooves found on it, each having one or two chamfers.
• the lateral groove or grooves may follow a straight path.
• the angle the grooves form with the lateral direction of the tire may range approximately from 0 to 45 degrees.
• the draft angles of the sidewalls range from 0 to 15 degrees.
• the tread of the tire further comprises circumferential grooves that together with lateral grooves define a plurality of tread blocks that have a length of approximately 35 mm in the circumferential direction of the tire.
• the tread blocks may have four sipes on them that are each spaced approximately 7 mm from either another sipe or a lateral groove in the circumferential direction of the tire.
• the size of the tire may be 245/45R17.
• FIG. 1 is a perspective view showing a tire with lateral grooves having chamfers according to an embodiment of the present invention with the lateral or axial, circumferential and radial directions of the tire also being shown;
• FIG. 2 is an enlarged fragmentary view of the tread block of the center rib as defined by the circumferential and lateral grooves of the tire of FIG. 1;
• FIG. 3 is a top view of the tire of FIG. 2 showing the angle the lateral grooves form with the lateral or axial direction of the tire;
• FIG. 4A is a side cross-sectional view of the lateral groove of the tire of FIG. 3 taken along line 4A-4A thereof;
• FIG. 4B is an enlarged view of one of the lateral grooves of the tire of FIG. 4A showing the angle the chamfer makes with the tangent of the circumference of the tire;
• FIG. 4C is an enlarged view of another of the lateral grooves of the tire of FIG. 4A showing the depth and width of the chamfers of the lateral groove;
• FIG. 4D is an enlarged view of a third lateral groove of the tire of FTG. 4 A showing the draft angle of the sidewal!s;
• FIG. 5 is a graph showing the optimal width of the lateral grooves of the tire of FIG. 1;
• FIG. 6 is a graph showing the optimal range of angles the sweep path of the lateral groove forms with the lateral direction of the tire.
• FIG. 7 is graph showing the optimization of the Snow Traction and Dry Braking performance of a tire by using an appropriately sized lateral groove with chamfer for a tread block with a given sipe density.
• a tire 100 with lateral grooves 102 that have chamfers 104 located where the grooves 102 intersect the circumference 106 of the tire is shown.
• the lateral grooves 102 are so called since they extend generally in the lateral or axial direction L of the tire, which is parallel with the axis of rotation of the tire.
• the tire 100 further comprises circumferential grooves 108 that extend generally in the circumferential direction C of the tire, which is the direction along which the tire rolls. They along with the lateral grooves 102, form tread blocks 110 along the circumference 106 of the tire 100.
• These grooves 102, 108 provide void within the tread for the consumption of water and snow to aid in wet and snow traction.
• there are four sipes 112 which are thin incisions that provide extra biting edges which also aid in the traction of the tire.
• the size of the tire is 245/45R17 and the length LB of the tread block 110 is 35 mm in the circumferential direction C of the tire and the width WB of the block is 24 mm in the lateral direction L.
• the distance Dcss from sipe to sipe in the circumferential direction C is 7 mm and the distance D C L S from a lateral groove to a sipe in the circumferential direction C is also 7 mm. It is known that increasing the number of sipes 112 and lateral grooves 102 typically increases snow traction but may not increase other performances of the tire such as wear. Therefore, it is contemplated tiiat other tread blocks having different dimensions and features could be used.
• the length LB of the tread block 110 could be 27 mm and it could have two sipes 112 such that the distance DCL S from a lateral groove to a sipe or the distance Dcss from a sipe to another sipe could be 9 mm.
• the distance D ss from a sipe to another sipe and the distance DCLS from a sipe to a groove could be different from each other.
• tread blocks 110 found in the center rib 113 of the tire it can be also be seen that the sweep axis or path 114 of the lateral groove 102 forms an angle a with lateral direction L of the tire.
• the lateral grooves 102 have a depth DLG that is measured from the tangent T of the circumference 106 of the tire 100 to the bottom 116 of the groove 102 in the radial direction R of the tire.
• the depth DLG is 7 mm for all the lateral grooves 102 but it is contemplated that this depth could be more or less for some or all of the
• the sidewalls 117 of the grooves 102 have a draft angle ⁇ that is 2.5 degrees for both sidewalls of all the lateral grooves but it is contemplated that this draft angle could be more or less for some or all of the grooves.
• the lateral grooves 102 also have a width WLG which is measured from the theoretical sharp corner of one side of the lateral groove 102 to the theoretical sharp corner of the other side of the groove.
• the chamfers 104 it can be seen that they form an angle ⁇ with the tangent T of the circumference of the tire. It is preferable if this angle ⁇ is 45 degrees as this is the optimal angle that allows the snow to enter and exit the groove 102 as the tire rolls into and out of the contact patch with the road.
• the depth Dc and width Wc of the chamfers is
• angles ⁇ such as 30 or 60 degrees, as well as other depths Dc and widths c of the chamfers, such as 1 or 3 mm, could be used as well.
• FIG. S is a graph that shows the optimal width W L c of the lateral groove 102.
• Four days of testing were conducted to see how the width LG of the lateral groove 102 with chamfers 104 affected snow traction.
• the snow traction test shown in this figure is an analytical measurement of the tire Mu-Slip curve under driving torque provided by a testing machine.
• the testing protocol involves measuring the average Mu, which is the coefficient of friction, and it ranges typically between 20% and 300%.
• the track on which the testing was conducted is a soft snow track and the CTI penetrometer is between 75 and 80. The average of the results for all four days of testing has been plotted.
• the average of the results for all four days showed some improvement in snow traction at a width LG of 2 mm.
• a lateral groove width WLG of approximately 2.6 mm the average results show a snow traction improvement of 10% which is significant.
• the most improvement in snow traction was experienced at a lateral groove width W L G of approximately 3 mm where the average of the results indicated that there is a 15% improvement in snow traction.
• a lateral groove width WLG of approximately 3.6 mm there was still an average improvement of 5% and there was virtually no improvement in snow traction at a lateral groove width WLG of approximately 4 mm.
• the lateral groove width WLG should range from 2 to 4 mm and preferably ranges approximately from
• the lateral grooves 102 may extend in directions other than in a purely axial or lateral direction L of the tire.
• the grooves 102 may extend in a substantially straight path as shown for the tread blocks of the center ribs in FIGS. 1 thru 3 but it is contemplated by the Applicant that the lateral grooves 102 may also zig-zag, undulate or move arbitrarily along a general sweep axis or path 114 and still fall within the scope of the present invention.
• FIG. 6 shows a graph that indicates what range of angles o, the sweep axis or path 114 of a lateral groove or grooves 102 may form with the lateral direction L of the tire 100 and still provide proper snow transversal traction.
• the dotted line represents the typical performance curve 118 that shows the relationship that typically exists between snow traction and dry traction.
• This graph is based on data taken from a standard dry braking test, shown along the vertical axis of the graph, and data taken from a standard snow traction test as previously described, which is shown along the horizontal axis of the graph.
• the dry braking test is a vehicle test where the braking distance of the vehicle, which is mounted with the tires to be tested, is measured on a hard asphalt surface.
• the tire performance usually moves up along the curve 118 and snow traction is not improved.
• the snow traction index is approximately at 75.
• the tire performance moves down along the curve 118 and the dry braking performance is not unproved.
• the dry braking performance index is approximately 96.
• a lateral groove 102 with a width WLG of approximately 3 mm and two chamfers 104 on either side of the groove allows both dry braking and snow traction performances to be improved simultaneously.
• This is represented on the graph by a data point 120 located above and to the right of the curve 118 that represents the typical dry braking and snow traction performances of a tire.
• lateral grooves with the appropriate width and chamfer or chamfers provide such critical and unexpected results is that they provide an improved way of capturing and releasing snow when the tire is used in a snowy environment.
• the chamfers and lateral grooves are properly sized and configured, the chamfers help the snow enter and exit the groove while the width of the groove helps to retain and expel the snow at the proper time.
• a chamfer be used as opposed to a radius so that sharp edges are formed at the circumference of the tire, which allow the edge to effectively bite onto the road surface to improve snow traction once the snow has been received into the groove.
• the present invention is not limited to any particular theory but to the structure that provides these critical, surprising and unexpected results.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Tires In General (AREA)

Priority Applications (7)

Applications Claiming Priority (1)

Publications (1)

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Country Status (7)

Cited By (10)

Families Citing this family (9)

Citations (8)

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• 2009
  • 2009-11-23 WO PCT/US2009/065521 patent/WO2011062595A1/en active Application Filing
  • 2009-11-23 BR BR112012012276A patent/BR112012012276B1/pt active IP Right Grant
  • 2009-11-23 US US13/511,100 patent/US20120267021A1/en not_active Abandoned
  • 2009-11-23 JP JP2012541058A patent/JP2013511438A/ja active Pending
  • 2009-11-23 CN CN200980162562.3A patent/CN102666135B/zh active Active
  • 2009-11-23 MX MX2012005851A patent/MX2012005851A/es not_active Application Discontinuation
  • 2009-11-23 EP EP09851541.4A patent/EP2504179B1/en active Active

Patent Citations (8)

Non-Patent Citations (1)

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